Technological Field
The described technology generally relates to a device and method for calibrating the measurement of the power of signals with a wideband radio frequency receive chain.
The described technology is particularly applicable in the field of wideband amplitude radiogoniometry for localizing emission sources in radio frequency bands.
Description of the Related Technology
A radio frequency receive chain is branched at the output of a receiving antenna and comprises an input block and a set of hardware modules and digital computation capability, for example a computation processor.
In the field of radiogoniometry, several receiving antennas and several receive chains are used to allow the measurement of the arrival direction of the signal coming from an emission source. In this field, several techniques exist. One of these is commonly used due to the simplicity of its implementation; this is amplitude radiogoniometry. The latter is based on the use of the power of the signals delivered by an array of directional antennas, the pointing of which is generally evenly distributed over the angular range of interest, very generally 360° in the horizontal plane to measure the relative bearing. For this radiogoniometry, it is necessary to have good measuring precision of the power of the radio frequency signal received by each receiving antenna. However, each receive chain causes its own specific measuring imprecisions. In order to obtain good measuring precision, it is necessary to calibrate each radio frequency receive chain.
A wideband receive chain is made up of a set of several processing modules, connected to one another by cables that may be several meters long.
It is known to use a system for injecting and measuring a calibration signal, which requires a wideband radio frequency signal generator injected at the input of the receive chain and a device for measuring the power of said radio frequency signal at the input and output of the receive chain. Such a system is complex and cumbersome.
U.S. Pat. No. 6,700,537 B1 describes a system for calibrating a wideband radio frequency receiver of a location system, including at least two processing channels. This patent proposes to use a single noise source for the calibration, the noise being distributed over the processing channels. This calibration system requires a system for distributing the noise toward the various channels and allows only a relative calibration between the various channels used.